Many medicaments have to be injected into the body. This applies in particular to medicaments, which are deactivated or have their efficiency remarkably decreased by oral administration, e.g. proteines (such as Insulin, growth hormones, interferons), carbohydrates (e.g. Heparin), antibodies and the majority of vaccines. Such medicaments are predominantly injected by means of syringes, medicament pens or medicament pumps.
A compact small scale peristaltic medicament pump is disclosed in DE 19 745 999. The pump comprises a delivery head, a drive unit for the delivery head, and speed control. The pump with the drive unit may be replaceably attached to a reusable backend in order to maintain a clean and sterile treatment by disposing the pump off and replacing it with a clean one after drug delivery.
WO 2008/040477 A1 discloses an injection arrangement with a peristaltic medicament pump, wherein the drive unit is integrated in the reusable backend rather than in the pump unit so the relatively expensive drive unit does not have to be disposed off every time the pump unit is replaced.
It is an object of the present invention to provide an improved pump unit and an injection arrangement.
The object is achieved by a pump unit according to claim 1 and by a injection arrangement according to claim 11.
Preferred embodiments of the invention are given in the dependent claims.
A pump unit according to the invention is replaceably attachable to a reusable backend of an injection arrangement for delivering a liquid medicament. The pump unit comprises a medicament inlet, a medicament outlet and a pump for delivering the liquid medicament from the inlet to the outlet. A medicament container is arranged in the pump unit and connectable to the medicament inlet. A fluid communication between the medicament container and the pump is establishable when the pump unit is attached to the reusable backend. As long as the pump unit is not attached to the reusable backend, the medicament container remains sealed, e.g. by a septum. The fluid communication may be established by mechanically causing a relative advancing movement of the medicament container towards a hollow needle for piercing the septum, the needle attached to the medicament inlet. Integrating the medicament container in the pump unit improves handling and ergonomics of the pump unit since the user has to deal with fewer parts. The overall reliability of the injection device is improved. By keeping the medicament container sealed before attaching the pump unit to the reusable backend, sterility of the content, e.g. a liquid medicament is ensured.
The pump unit may also have at least one hollow injection needle for piercing a patient's (P) skin and administering the medicament or an adapter for attaching the at least one hollow injection needle integrated, thus further reducing the part count.
The needle may be a pen needle or a Luer needle or a micro-needle of a needle array.
The medicament container may have the shape of a standard ampoule or be a container with a flexible wall.
Preferably a flow sensor for determining a volume flow of the medicament is arranged in the pump unit and connectable to a control unit of a reusable backend thus allowing to control the volume of medicament to be delivered.
The flow sensor may be a thermal sensor or a magnetically inductive sensor or an impeller sensor.
The pump may be a peristaltic pump or a gear pump or a diaphragm pump.
The pump unit may further have at least one interface for connecting to a reusable backend. The interface may be one of a mechanical, electrical, optical, acoustic, magnetic and wireless electromagnetic interface. Preferably the interfaces are arranged to be easily disconnectable.
The mechanical interface may be arranged for connecting the pump to a drive unit arranged in a reusable backend, e.g. the mechanical interface having the shape of a gear or a clutch.
The pump unit is one of two major components of an injection arrangement for delivering a liquid medicament, the other major component being a reusable backend, comprising a control unit, a drive unit and an energy source.
The energy source for the drive unit may be a galvanic cell or battery of galvanic cells in case the drive unit comprises an electrical motor. Preferably the energy source is a rechargeable accumulator. The rechargeable accumulator may be replaceable or chargeable in place by an external charging device arranged for holding the reusable backend.
The reusable backend may further have a user interface for user interaction. This may comprise a dosing and/or trigger knob or wheel and/or a display, e.g for displaying a dose volume.
A second septum may be arranged at the medicament outlet. The second septum is pierced upon attaching a pen needle to the pump unit. Both the second septum and the pump serve for avoiding delayed dripping of medicament after injection. By means of the second septum and the pen needle the pump unit may be used for delivering more than one bolus of medicament while the interior of the pump unit is kept sterile between administration of the boluses.
The pump unit or the reusable backend or the injection arrangement may preferably be used for delivering one of an analgetic, an anticoagulant, insulin, an insulin derivate, heparin, Lovenox, a vaccine, a growth hormone and a peptide hormone.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.